A Guide for Sewing Quality Jeans at Home
 

When choosing a fabric you should take into account the following:

1.  Closeness of fit
     Generally the closer the fit the more stretch the fabric should have.

2.  Durability

3.  Weather
     Thicker fabrics will generally keep you warmer, while thinner fabrics keep you cooler.

4.  Desired Coloring

Many denim fabrics sold at fabric stores are very thin and are intended for lightweight skirts or shirts, avoid these.  Also avoid the light blue denim fabrics unless you are trying to make jeans that look out of style.  I always go for the dark-washed indigo fabrics because they always look the best.  Pretty much any medium to heavyweight denim will do the job though.

I also try to find denim with some stretch to it.  1% or 2% spandex is good, but you should pay more attention to the actual stretch of the fabric than the spandex content.  Fabric with good stretch actually lasts a lot longer and does not tare as easily.  You can often find 100% cotton or cotton polyester blends that have a significant amount of stretch to them.

The fabric you use for the pocket lining is pretty easy to come by.  I usually just use a sturdy woven fabric that has very little stretch

Also make sure you prewash all the fabrics you use because they can shrink a lot.    I usually prewash in warm water.  I noticed that even after prewashing the fabric the jeans tend to be a little tighter after washing them the first time.